1. Technical Field of the Invention
The present invention relates to the field of tracking devices, and more specifically to weathervane stowage of tracking devices.
2. Background
Tracking structures are required for a variety of applications, from optical and radio telescopes viewing celestial objects to solar systems tracking the sun to cameras tracking moving objects to radar viewing flying objects both within and beyond earth's atmosphere. Tracking structures may also have a function of reflecting incoming radiant or acoustical energy and delivering focused energy to a point as with a focusing solar system or an acoustical focusing system. These tracking systems may have the goal of tracking the sun or other celestial body with the goal of concentrating the incident incoming energy. This requires dynamic movement of the tracking structure in both azimuth and elevation. It is usually desirable for the tracking structure to present the maximum square footage of incident surface area to the oncoming radiation (as with a solar concentrating system), light (as with a telescope), or reflected signal (as with a radar or sonar dish). The tracking mechanisms must be designed to be strong enough to position these large surfaces very accurately, to endure high wind conditions, and also to minimize the damage from any particulate material carried with the wind, such as dust, sand, and hail. New technologies offer lightweight and less costly materials for receiving incident energy, such as reflective film or thin glass for solar concentrators. The author's U.S. Pat. No. 7,374,301 discusses one such lightweight concentrating reflector. While these new lightweight materials can further reduce the weight and cost of the tracking structure during normal operation, large surface areas still present a significant aerodynamic load on the tracking structures during high wind conditions. The cost and weight of a tracking structure may be required to be much greater to endure these infrequent but potentially catastrophic wind events. Wind also can act as a vehicle to carry sand, hail, and other particulate matter which can mar the reflective or other incident surfaces, decreasing their viability over time.